So without telling me, my dad went on craigslist to buy an iPhone and got scammed. He thought he was getting an unlocked white iPhone 4S and instead got an ATT locked iPhone 4 8gb and my whole family is on T mobile (facepalm). Anyways I have an old iPhone 4 that I kept as a backup phone with cracked screen, malfunction home button and broken proximity sensor.The only good thing about it is that I got it factory unlocked thru ATT in the early days when they were unlocking phones left and right. So if I swap out the logic board of the two phones, would the factory unlock transfer over to the newer white iPhone 4?